Integrated circuit packages are generally of a rectangular configuration with contacts or leads arranged along the edges of the package to provide connections to the interior circuitry.
It is necessary to test the circuitry in the integrated circuit packages before it is installed in a product to determine that the interior circuitry has been properly established and is suitable for its intended use, and also to test such packages for any subsequent failure after initial installation. In addition, it is frequently desirable to burn-in such packages as a technique for eliminating packages which would fail after a short period of time. In such burn-in testing, the package is stressed electrically, thermally and/or environmentally for a preselected period of time. Test sockets have been devised for these integrated circuit packages to test the circuit packages and to burn-in such circuit packages, as well as for experimental circuit applications.
As utilized herein, "test socket" includes sockets for testing, burning-in and experimental circuit applications.
Some test sockets currently sold by the Textool Division of Minnesota Mining and Manufacturing Company of St. Paul, Minn., have a body with a recess and contact elements thereabout to make electrical contact with terminals about the integrated circuit package. This socket has a cover hinged on the body to pivot downwardly thereagainst and then latch to the body. The cover has a pressure pad to force the terminals on the package against the contact elements.
A test socket sold by Plastronics Inc. of Irving, Tex. has a body with a top opening into which the package is inserted and contacts thereabout to make electrical connection to the terminals along the sides of the package. The package is released by inverting the socket and the printed circuit board to which the socket may be soldered, and pressing down on the board which depresses the socket to release and allow the package fall out. This construction is generally shown in Pfaff U.S. Pat. No. 4,491,377.
A socket presently made by the assignee of the present invention has a cavity into which the package is inserted and contacts thereabout to make electrical connection to terminals along the sides of the package. This test socket has a support and ejection mechanism including a spring-biased platform which may be pushed downwardly in the cavity past a cam lock. When the downward pressure is removed, the cam lock engages the platform to hold it in the depressed test position. Pressing on the package a second time disengages the cam lock and releases the platform which then moves upwardly carrying the package to the top of the socket. The structure is illustrated and described in Hexamer et al U.S. Pat. No. 4,498,047.
Kelley U.S. Pat. No. 4,533,192 illustrates a test socket which utilizes complex shaped contacts to mechanically lock an integrated circuit package therein under the contacts. It has a camming member and spring biased platform to flex the test socket contacts out of locking engagement with the circuit package terminals to permit removal of the circuit package.
Although these test sockets all perform the desired functions, there are often problems in case of package removal or proper electrical contact force, and/or access to and observation of the package during testing.
The present invention is directed to a new and improved test socket for integrated circuit packages which is of relatively simple construction and which permits easy top insertion and top removal of a circuit package.
Another object is to provide such a test socket which provides good electrical contact with the contacts of the circuit package and which permits observation of the package.
Still another object is to provide such a test socket which is adapted to use in automated installations.
A further object is to provide such a test socket with good wiping action on the contacts of the circuit package.